^1Π态双原子分子中关于∧量子干涉的微分干涉角

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角（J.Chem.Phys.,1995,102：2772）.由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的^1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

1Π态双原子分子中关于(A)量子干涉的微分干涉角

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,102:2772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

1~Π态双原子分子中关于Λ量子干涉的微分干涉角(英文)

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,102:2772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

1Π态双原子分子中关于量子干涉的微分干涉角

Sha等在静态池实验中观察到了转动能量转移中的碰撞量子干涉,并且计算了决定跃迁散射截面的积分干涉角(J.Chem.Phys.,1995,1022772).由于积分干涉角是微分干涉角的平均效应,为了得到更精确的信息,进行了分子束实验.作者文运用含时微扰的一级波恩近似理论,提出了衡量干涉程度的1П态双原子分子中关于Λ量子干涉的微分干涉角.利用各向异性相互作用势计算了其干涉角.得到分子束实验中微分干涉角随实验参数,包括实验温度、碰撞伴、作用距离和转动量子数变化的关系.并且讨论了影响干涉角的各种参数.此理论模型对理解和进行分子束实验是非常重要的.     

分子单重/叁重混合激发态碰撞传能中的量子干涉效应

量子干涉效应是基于量子力学波粒二象性原理,即微观粒子的运动皆具有波的特性而产生的一种干涉现象,故又称为物质波干涉.近年来,在分子的光激发、光解和光电离及碰撞过程中皆已观察到量子干涉效应,成为分子动态学领域研究热点之一.我们小组在国际上首次得到了单重/叁重混合激发态分子碰撞传能中的量子干涉的实验证据,从理论上导出了包括干涉相位角的传能截面公式,从实验上发展了激光双共振多光子电离光谱技术,用以测定了CO(A1П,v=0/e3∑-,v=1)与各种原子(He,Ne,Ar)及双原子分子H2,O2,N2,HCl碰撞传能的干涉角.其后又与李丽的小组合作,在热管炉中用激光双共振诱导荧光法观察到Na2(A1∑+uv=8/b3П0u,v=14)-Na碰撞中的量子干涉效应,证明了碰撞干涉效应的普遍性.近年来,在理论方面,我们发展了基于含时微扰的一级波恩近似量子散射方法,计算出了上述碰撞体系的干涉角θST,与实验值符合极好.本文指出虽然气池实验测得的干涉角θST是不同分子碰撞速度及碰撞参数的"平均"结果,但与理论计算的微分干涉角尚比较接近,可提供激发态分子碰撞相互作用势的重要而难得的信息.     

激光光热干涉光谱分析方法研究

本工作设计了一种新的激光光热干涉光谱装置,类似于Mach-Zehnder干涉仪的光路构型,采用探测束聚焦和泵浦束与探测束相交的光学结构,光路容易调整稳定性较好.文章讨论了方法的原理,详细研究了影响光热干涉信号的实验参数,获得结晶紫的检测下限为8.0×10~(-8)mol/L,相应的最小吸光度为3.6×10~(-6)。     

基于纳米多孔薄膜光学干涉的光学传感器

光学传感器是一种利用光把介质与目标分子的相互作用转换为光信号的装置.光学干涉是光学传感器中常用的技术,具有无需标记、无破坏性、响应迅速等优点.在光学传感器中光的干涉主要源于从单层薄膜上下表面反射的光或者从多层薄膜各个界面处反射的光.由于纳米多孔薄膜具有较高的比表面积,将其应用于传感器中能够提高传感器的灵敏度、降低检测限.常见的薄膜类型主要有单层、双层、多层（光子晶体）等.本文综述了多孔硅、阳极氧化铝、二氧化钛、金属有机骨架等纳米多孔薄膜材料的光学干涉在传感器中的应用,并对其进行了展望.     

基于干涉图解析的被动式遥感FTIR分析

针对被动式遥感傅里叶变换红外光谱(FTIR)在实际应用中存在受环境干扰较大,检测信号较弱的问题,利用背景和样品干涉图的衰减速度不同,建立了基于干涉图对被动式遥感FTIR谱图进行分析的方法. 选择有限脉冲响应(FIR)滤波器提取信号,带宽选择为20 cm-1,干涉图长度为100点,距离中心爆发点(centerburst)第50点为干涉图起始点,对样品苯的被动式遥感FTIR信号进行了有效提取. 然后采用偏最小二乘法(PLS)建立模式识别模型,对26个未知样品的干涉图数据进行预测,总识别率为96%. 该方法的建立,减弱了背景对遥感测试的影响,强化了被动式FTIR的分析信号,同时与化学计量学方法结合实现了被动式遥感FTIR对污染物的自动检测.     

锥光干涉法表征偶氮苯侧链液晶聚合物的光致取向

采用偏光显微镜在平行光和锥光条件下对液晶聚合物膜内分子的取向排列状态进行了研究,不同取向状态的膜由线偏振光或圆偏振光照射偶氮苯侧链液晶聚合物得到。结果表明,液晶聚合物膜采用线偏振光照射时,偶氮苯介晶基元沿面排列,形成单相畴面内取向态。该取向态的锥光干涉图为位于视场中心的粗黑十字,旋转载物台小于10°,该干涉图即完全退出...     

基于影像处理的干涉测量相位重构研究

随着计算机技术和光电成像元件的发展,影像信息处理技术已经在无损检测、医学检测以及干涉测量等领域得到广泛应用。本文主要研究了影像信息在干涉测量领域的波前相位提取方法。干涉条纹图是干涉测量领域中影像信息的载体,在干涉条纹处理方面,针对空域卡雷算法的特点,提出一种基于影像处理的单幅闭合干涉条纹图相位重构新算法。在空域卡雷算法处理方法的基础上,利用迭代修正算法对干涉图相位进行二次逼近,实现了对单幅干涉条纹图的高精度相位重构。Matlab仿真结果表明,迭代修正后的相位残差降低了25.8%,表明该算法在空域卡雷算法的基础上能够有效提高相位重构精度,实现干涉测量领域中影像信息的高精度处理。     

∧-related Quantum Interference of ^2П [Case（a）] Diatom on Rotational Energy Transfer

To study theoretically the relationship between the integral interference angle and the scat- tering angle in collisional quantum interference, the integral interference angle of atom- ^2П[case（a）] diatomic molecules system is described. To simulate the experiment theoretically, the theoretical model on collision-induced rotational energy transfer in an atom- ^2П[case（a）]diatom system is presented based on the first order Born approximation taking into account of the long-range interaction potential. For the ^2П electronic state in the Hund＇s case（a） diatom, the degree of the interference is discussed. The interference angles of collision-induced rotational energy transfer of CN（A^2П） in Hund＇s case（a） with He, Ne, and Ar are calculated quantitatively. The key parameters in the determination of integral interference angles are obtained.     

Adsorption of heavy metal ions from aqueous solution by polyrhodanine-encapsulated magnetic nanoparticles

The influence of salt concentration on the terminal velocities of gravity-driven single bubbles sliding along an inclined glass wall has been investigated, in an effort to establish whether surface forces acting between the wall and the bubble influence the latter's mobility. A simple sliding bubble apparatus was employed to measure the terminal velocities of air bubbles with radii ranging from 0.3 to 1.5 mm sliding along the interior wall of an inclined Pyrex glass cylinder with inclination angles between 0.6 and 40.1°. Experiments were performed in pure water, 10 mM and 100 mM KCl solutions. We compared our experimental results with a theory by Hodges et al. which considers hydrodynamic forces only, and with a theory developed by two of us which considers surface forces to play a significant role. Our experimental results demonstrate that the terminal velocity of the bubble not only varies with the angle of inclination and the bubble size but also with the salt concentration, particularly at low inclination angles of ～1-5°, indicating that double-layer forces between the bubble and the wall influence the sliding behavior. This is the first demonstration that terminal velocities of sliding bubbles are affected by disjoining pressure.     

Interference technique in grazing-emission electron probe microanalysis of submicrometer particles

The distribution of X-ray radiation from a small particle, situated on a flat support and excited by an electron beam, is analyzed theoretically. The interference pattern, appearing within the region of grazing take-off angles, is shown to contain valuable information about the particle structure and composition. It also provides the resources for extracting this information that are valid even in conditions of extremely low signals (e.g. for very small samples), when the effect of background suppression for angles of the total reflection region is insufficient. Characteristic elements of the interference pattern are found that are relatively independent on the noise caused by the support radiation. Algorithms for this noise correction and elimination are proposed. An approximate formalism for the particle structure retrieval, based on the Fourier-transformation properties, is described. Potential applications of the proposed technique are illustrated with numerical models of spherical and hemispherical particles, both homogeneous and of ‘core-and-shell’ structures, with total sizes between 30 and 200 nm. The additional possibilities of studying the shape, structure and elemental composition of small particles have been demonstrated. The general conditions of the experimental realization of proposed methods are discussed.     

Crossed beam scattering experiments with optimized energy resolution

Crossed molecular beam scattering experiments in which the energy of the collision is varied can reveal valuable insight into the collision dynamics. The energy resolution that can be obtained depends mainly on the velocity and angular spreads of the molecular beams; often, these are too broad to resolve narrow features in the cross sections like scattering resonances. The collision energy resolution can be greatly improved by making appropriate choices for the beam velocities and the beam intersection angle. This method works particularly well for situations in which one of the beams has a narrow velocity spread, and we here discuss the implications of this method for crossed beam scattering experiments with Stark-decelerated beams.     

A refractive tilting-plate technique for measurement of dynamic contact angles

The contact angle is a critical parameter in liquid interface dynamics ranging from liquid spreading on a solid surface on earth to liquid motion in partially filled containers in space. A refractive tilting-plate technique employing a scanning laser beam is developed to conduct an experimental study of a moving contact line, with the intention of making accurate measurements of the contact angle. The technique shows promise as an accurate and potentially fully automated means to determine the velocity dependence of the contact angle at the intersection of the interface between two transparent fluids with a transparent solid surface. Ray tracing calculations are included to reinforce the measurement concept. The principal experiments were conducted at speeds ranging from 0.05 to 1.00 mm/s, both advancing and receding, using an immiscible liquid pair (nonane/formamide) in contact with glass. The contact angle was found to depend for practical purposes only on the sign of the velocity and not on its magnitude for the range of velocities studied. Other observations revealed a bimodal behavior of the contact line that depends on which liquid first contacts the glass, with resulting drift in the dynamic contact angle with time.     

Mechanical anisotropy in biaxially oriented polyvinyl chloride

The mechanical anisotropy of polyvinyl chloride oriented in two perpendicular directions with different draw ratios has been studied. The results are compared with the anisotropy of uniaxial samples oriented at a common draw ratio. The propagation velocities of ultrasonic pulses have been measured by an immersion technique. Longitudinal wave velocities have been measured in three principal planes over a wide range of propagation directions. The limitations of measuring velocities in the planes containing the draw axes were mitigated by use of a special slicing technique. Measurements were performed at 2 MH_z and 25°C. Velocities of the transverse waves were measured for incident wave angles greater than the critical angle. From these measurements, five elastic moduli were calculated for the uniaxially oriented samples, and nine elastic moduli were obtained for the biaxially oriented samples. In biaxially oriented samples, the moduli along the draw axes are directly proportional to the draw ratio in the same direction.     

Collision-induced Rotational Energy Transfer in an Atom-Diatom System

As a further theoretical study of the collision-induced quantum interference on rotational energy transfer in an atom-diatom system, based on the first-Born approximation of time-dependent perturbation theory, taking into account the anisotropic Lennard-Jones interaction potential and the long-range interaction potential, the differential interference angles in singlet-triplet mixed states of CO A1Ⅱ(v=0)～e3∑-(v=1)system in collision with He, Ne, Ar, and other partners were calculated theoretically. The relationships of differential interference angle versus impact parameters, including collision parameter b and velocity, are obtained.     

Velocity dependence of impact line-broadening studied by resonant doppler-free two-photon laser spectroscopy

The velocity dependence of the collison broadening of the⁴⁰Ca 4s ^{2 1} S ₀→4s5p ¹ P ₁ →4s17d ¹ D ₂ transition by neon atoms has been studied. The experiment was performed exciting one velocity group of Ca atoms within the Doppler profile of the first transition and probing this group with a counterpropagating laser beam inducing the second transition. Using thermionic detection we have measured broadening rates for relative velocities between Ca and Ne atoms which corresponds to a temperature range of about 850 K (cell temperature) to 3000 K. The measured line-width was found to have very weak temperature dependence. This is attributed to the weak velocity dependence of polarization broadening of the final level which was found to be the major contribution to the broadening of the two-photon line. For large relative velocities significant asymmetries in the measured line profiles due to velocity changing collisions had to be taken into account.     

Effect of orientation on thermoset frontal polymerization

We observed that the velocities of descending thermoset polymerization fronts were strongly affected by the orientation of the tube. The front remained approximately perpendicular to the gravitational vector but propagated almost 1.8 times as fast at 75° along the axis of the tube. We performed a study of the velocity and front‐shape dependence on orientation with propagating fronts of triethylene glycol dimethacrylate with peroxide initiator and acrylamide/bisacrylamide polymerization in dimethyl sulfoxide with persulfate initiator. The percentage increase of velocity was independent of the initiator concentration but strongly dependent on the viscosity. Convection under the front flowed away from the tube wall nearest the vertical axis and was stronger as the angle increased. The front shape also changed, becoming significantly distorted near the wall from which the convection originated. We applied a simple geometric argument to explain the angular dependence for small angles on the basis of the assumption that convection did not affect the velocity of propagation normal to the front. The increase in velocity along the tube axis could be explained by a projection of the normal velocity onto the tube axis, following a 1/cosθ dependence. For higher angles, the convection was not sufficiently strong to maintain a level front. When the difference from a 180° orientation was considered, the velocity dependence exactly followed the geometric relationship. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3504–3508, 2002